Mobile network operator Cubic Telecom, which runs the MAXroam cut-price roaming MVNO, has inked a deal worth “tens of millions” of dollars with Australian retail giant Woolworths. Maxroam’s virtual SIM (multi-IMSI) technology is being used to power a new global roaming product from Woolworths’ own MVNO, Woolworth Mobile.

The global roaming SIM is branded solely as a Woolworths Mobile product — a sign, says Cubic Telecom Director of Product and Innovation Pat Phelan, of the “extreme trust” between the two companies.

“This is an enormous deal for us. This is the biggest deal we’ve ever done,” he tells TechCrunch. “Woolworths are a $55 billion company… we’ve been dealing with them for two years — we’ve branded the product as the exact same brand as their existing MVNO. You can imagine if something goes wrong with our deal it’s their MVNO ruined as well. So there’s been extreme trust between the companies.”

Woolworths is the first global company to join the Cubic Platform, Phelan adds.

Cubic Telecom was founded in Ireland in 2005 and has raised some $6.7 million in funding to date. It owns and operates a core mobile network in Europe and partners with other mobile operators globally to be able to offer local rates for voice and data roaming. For example, in the U.K. MAXroam partners with Vodafone U.K. to offer cheaper roaming rates. “What happens is when [a MAXroam SIM] lands in the UK our platform switches that SIM completely local on Vodafone UK. So they’re not roaming anymore they’re actually at home,” Phelan explains.

The catalyst for the Woolworths deal are the eye-wateringly expensive roaming charges Australians typically have to pay. Phelan notes that an Australian visiting the U.K. can be charged $15 per megabyte for data, while data roaming costs in other locations can be as high as $20 per megabyte. Even voice calls in popular destinations for Australians to travel to, such as China, can cost as much as $6 per minute.

The Woolworths Mobile global roaming SIM is being marketed with a claim it can cut roaming charges by up to 90%. It costs $29 (which includes $10 of credit), and can be used in any unlocked handset. The SIM, which can be used in standard or micro SIM size, supports roaming in more than 230 countries. MAXroam notes that a visitors to the U.K. will be able to use the SIM to make calls anywhere in the world for 18c per min, while all incoming calls are free of charge. Data costs from $7 for a 250MB bundle.

From tomorrow, Woolworths Mobile will also be offering a nano SIM version of the global roaming SIM — to make the product compatible with Apple’s iPhone 5. According to Phelan, this will make it the first nano SIM up for grabs from an MVNO — or, in other words, the only option at present for iPhone 5 owners wanting to roam more cheaply than whatever pound of flesh their operator wants to wring out of them.